Olawale Ayoola BADIRU2024-05-232024-05-232022-12Kate TurabianM.Schttps://repository.lcu.edu.ng/handle/123456789/321The increase in emerging antibiotics resistance bacteria to prevailing infection and side effects of antibiotics drug’s efficacy has led to emphasis on the use of plant extracts and its derivatives as a source of medicine for vast categories of human ailments. This research work specialized in phytochemical screening and the antimicrobial activities of Croton zambesicus evaluation. The effects of the plant extract parts were examined in-vitro using petroleum ether, ethanol, acetone, chloroform and aqueous at different concentrations on pathogenic bacteria including E. coli, S. typhi, E. cloacae, P. mirabilis, K. pneumonia, and S. aureus. The MIC effects for E. coli recorded 1.53mm on ethanol, 1.46mm on petroleum ether, 2.9mm on acetone. S. typhi was reactive to petroleum ether at 1.53mm, E. cloacea recorded 1.0mm on ethanol, 1.6mm on petroleum ether and 1.08mm on acetone, P. mirabilis measured 1.0 on petroleum ether, and 2.0 on acetone. K. pneumonia accounted 1.0 on ethanol, 0.51 on petroleum ether and 2.09 on acetone. The result of the standard antibiotics test discovered that S. aureus was inhibited by chloramphenicol (17mm), esperfloxacin (13mm), streptomycin (17mm), erythromycin (14mm), pefloxacin (16mm), gentamicin (20mm), septrin (20mm), ciprofloxacillin (19mm) and rocephin (16mm), K. pneumonia was inhibited bypefloxacin (15mm), rocephin (11mm), Esperfloxacin (13mm) and ciprofloxacillin (12mm). S. typhi was inhibited by rocephin (14mm), chloramphenicol (15mm), Esperfloxacin (12mm), ciprofloxacillin (11mm), Zinnacef (11mm), pefloxacin (19mm), septrin (17mm), erythromycin (14mm) and streptomycin (16mm). P. mirabiliswas inhibited by esperfloxacin (16mm), rocephin (10mm), ciprofloxacillin (11mm), gentamicin (9mm), pefloxacin (17mm), erythromycin (11mm), streptomycin (14mm), and chloramphenicol (10mm). Phytochemical analysis of C. zambesicus revealed the presence of alkaloid, saponins, terperoid, steroid, flavoroid, glycosides, and triterpenes. The plant parts were proven to show that phytochemical derivatives contain antimicrobial properties and acetone and ethanol being an excellent solvent extractor. Keywords: Croton zambesicus, Minimum inhibitory concentration, Antimicrobial activity, phytochemical screening and bacteria isolates. Word Count -.287enThesis